1994 4.3L Mercruiser Cold Start Problem

[curtyoung]

I have a 1994 Ebbtide Campione 1900 with a 4.3L Mercruiser I/O. The engine has been well taken care of during its light use.<br /><br />The problem is that I have had a terrible time lately getting the engine started after it has sat cold for a day or two. Once started and warm, it runs beautifully and starts and idles perfectly. Now I can't seem to get it to start at all and have killed two batteries trying. I engage the choke on the throttle handle full then back 1/4 as written in the owners manual. Still won't start even after pumping the throttle with choke engaged. <br /><br />I doubt it is flooding since it doesn't appear to be getting any gas at all. There is no gas smell at all when I lift the engine cover.<br /><br />Any ideas of what could be wrong? I'm guessing a faulty fuel pump or clogged line?<br /><br />Thanks!

 

[Bondo]

Re: 1994 4.3L Mercruiser Cold Start Problem

Change the Fuel Filter ???????

 

[McKenzie]

Re: 1994 4.3L Mercruiser Cold Start Problem

an easy way to eliminate fuel problems is to look down the carb while cranking, is fuel spraying in? Also, push the accelerator pump arm a few times, does it feel stiff and shoot fuel into the carb barrels?

 

[tylerin]

Re: 1994 4.3L Mercruiser Cold Start Problem

Bondo is right start with the cheap stuff

 

[ctak]

Re: 1994 4.3L Mercruiser Cold Start Problem

Does this 4.3 have an electric fuel pump on it? If it does you can check if it is pumping properly by taking a wire from your battery to the inputs for your pump and check to see that its working (you can hear it pumping). I've had starting problems with my 4.3LX also. After you check the pump and its working check the connections to your oil pressure sensor, its located down above the oil pan. If the connectors are corroded and not getting proper connection then your engine either will start then shut off or not start at all. Also check the connectors to the oil sender and temp sensors. Another area to check is the kill switch. If your boat has one by the controls. This little switch caused my hours of grief, because it was intermittent. Anyway you can rule it out by shorting across the terminals with a piece of wire or jumpers. I got mad and soldered the terminals together. Hope this helps.

 

[curtyoung]

Re: 1994 4.3L Mercruiser Cold Start Problem

Thanks guys I appreciate all the support. I will attempt replacing the gas filter first as bondo suggests. Any tips doing this such as priming, etc?<br /><br />I did the carb check as McKenzie suggested, and no gas is spraying into the carb. The arm does feel stiff, but no fuel spray. Could this still be from a clogged fuel fiter problem?<br /><br />I do have a kill switch on the throttle and have never turned it off from the RUN position. Could this cause it to short out?<br /><br />My starting problem has been one of it progressively getting harder and harder to start when cold. Turns over just fine, and once started, runs perfect. Restarts quickly and no problems idling at all. Now it just won't start at all.<br /><br />Thanks again all!

 

[akriverrat]

Re: 1994 4.3L Mercruiser Cold Start Problem

maybe electric fuel pump not getting power.

 

[curtyoung]

Re: 1994 4.3L Mercruiser Cold Start Problem

Thanks akriverrat, the fuel pump was my first thought. Would the fuel pump cause the "hard to start cold but runs fine warm" problem?

 

[magster65]

Re: 1994 4.3L Mercruiser Cold Start Problem

If your accelerator pump isn't working your carb obviously needs help. It sounds to me as if the pump itself is sticking but loosens up after using it a bit. Install a carb kit... very common problem and quite a few posts on it lately.

 

[McKenzie]

Re: 1994 4.3L Mercruiser Cold Start Problem

If the accelerator pump arm felt stiff, that means that gas is most likely reaching the carb. Since the accelerator pump didn't shoot any gas into the carb, it's safe to assume that there is a blockage within the carb. You can clean and rebuild it, but if you don't feel comfortable doing this, you might wanna try a "mechanic in a can". Get an outboard motor gas tank, connect it to your fuel pump and fill the tank with a gallon or two of gas and add a can of Seafoam. Get the engine running (you will probably have to use starting fluid). Run the engine until it empties the tank. If you are lucky, that will clean up this problem and save you the trouble of rebuilding the carb. I did this to a friends boat, solved just about all his problems, rough idle, hesitation, and high rpm miss. Did this to my boat too, ran much better and gained 3 mph. If it doesn't work, it was worth a try and you gotta rebuild the carb. BTW, you can get Seafoam at NAPA.

 

[akriverrat]

Re: 1994 4.3L Mercruiser Cold Start Problem

electric pump gets voltage from 2 sources.see these...http://www.marinemechanic.com/2000/chfacts/elec_fuel.htm and http://www.marinemechanic.com/New-Folder2/est-no-msts-eng-wrg.htm it may not be getting reliable voltage till oil pump pressurizes system. iwould be checking safety switch.

 

[curtyoung]

Re: 1994 4.3L Mercruiser Cold Start Problem

Wow you guys are all great. Since I am not that mechanically inclined, it seems that my best bet is to turn it over to a Mercruiser mechanic. <br /><br />I replaced the fuel filter, primed it, and still nothing happended, so it does appear to be somthing with getting the fuel pump to kick in. I checked the line out of the pump and it is bone dry. Put some gas in the carb and it started right up...then died since no more gas is getting into the carb. I'm thinking less of a carb probem and more of a power to the fuel pump or bad fuel pump. Or could it be the kill-switch is causing it? <br /><br />FYI, here's an email I received on my problem. Do you guys agree?<br /><br />"Yours is a common complaint with the 4.3L engine. Since oil pressure activates the electric fuel pump there is a lag time before the fuel pump kicks in.<br /><br />The first thing to do is make sure the choke is closing properly. Advance the throttle until the choke snaps closed. It has to close completely with no noticeable air gap. If it doesn't close properly, adjust the choke.<br /><br />Next time you go to start the engine.. be sure to open the throttle a little then, crank the engine until you see about 10 to 20 psi of oil pressure, on the oil pressure gauge. Release the key but do not turn the key off. The fuel pump will run until the oil pressure drops to zero. After about 15 seconds, repeat the cranking procedure. By the third attempt, it should start."

 

[dfb]

Re: 1994 4.3L Mercruiser Cold Start Problem

I had similiar problem 2-years ago. I put a primer bulb on the line between tank and fuel filter. No problems starting boat since then. I just squeeze bulb 3-4 times and she starts. The rest of the day the boat starts without problems.<br />dfb

 

[Bopper1]

Re: 1994 4.3L Mercruiser Cold Start Problem

I had a similar problem with not getting any fuel with the same engine. The line from the fuel filter to the tank was bone dry also. I replaced the anti-syphon valve and now I get fuel atleast. The engine will fire when cold but only runs 10 - 15 seconds. Sounds like I might have the same situation with the oil pressure and the fuel pump. I'm going to give that suggestion in the email a try.

 

[Sailhog]

Re: 1994 4.3L Mercruiser Cold Start Problem

did you solve the problem? I have the same issue with the same motor and year of motor? I was told to change the anti-siphon valve.

 

[Bopper1]

Re: 1994 4.3L Mercruiser Cold Start Problem

I haven't had a chance to try yet. The anti-syphon valve atleast keeps the fuel in the line now. I was also told today by a marine mechanic that the electric fuel pump bypasses the oil pressure switch in cranking mode. He suggested that the distributor cap might have moisture, but that doesn't make sense to me if the engine runs fine for 10-15 seconds. It is like it runs out of gas. However, when I then pump the throttle a couple of times I have watched the fuel squirt into the carb, but cranking it still doesn't fire the engine. It is almost like vapor lock except that vapor lock is supposed to happen when everything is hot. I have then squirted a tiny shot of starting fluid into the carb, put everything back together and then the engine fires and keeps running. I have done this the last 3 times I used the boat after it sat overnight and it is the same senario evey time. I really don't like getting into the carb and using starting fluid every time. Once it starts it runs great and starts fine if I stop it. Any good ideas?